The present invention relates to a dustproof device for a ratchet wrench and, more particularly, to a dustproof cap mounted in a recess in a side of a head of a ratchet wrench to prevent dust and debris from entering a gap between the head and a driving member rotatably received in the head.
FIGS. 1A and 1B show a conventional ratchet wrench 10′ including a head 12 connected to an end of a handle 11. The head 12 includes first and second sides F1 and F2. A compartment 121 extends from first side F1 through second side F2 and rotatably receives a driving device 2. A recess 13 is formed in second side F2 and in communication with compartment 121. Compartment 121 has an opening in first side F1, which opening having a diameter smaller than compartment 121, forming an annular end wall 122. A first groove 124 is formed in an inner periphery of compartment 121. A second groove 125 is formed in a wall of second groove 124 and has an opening in first side F1. First groove 124 is intermediate second groove 125 and compartment 121. First groove 124 is spaced from recess 13 by a partitioning wall 123. An annular groove 126 is formed in the inner periphery of compartment 121 and is at the same level as and in communication with recess 13. Driving device 2 includes a drive member 21 having a lower, coupling portion 211. Drive member 21 further includes an upper, cylindrical portion having a larger diameter. A toothed portion 213 is formed on an outer periphery of the cylindrical portion. A stepped portion 212 is formed at an intersection of the cylindrical portion and coupling portion 211. An annular groove 214 is formed in the outer periphery of the cylindrical portion and between stepped portion 212 and toothed portion 213 and aligned with annular groove 126 and recess 13. Drive member 21 includes a longitudinal through-hole 2151 with an enlarged section 2152. A push rod 20 is received in through-hole 2151 and includes a smaller actuating section 201. A spring 202 is mounted in enlarged section 2152 and around actuating section 201. A ball 23 is mounted in coupling portion 211 for engagement with a workpiece such as a socket. Push rod 20 can be pushed to release ball 23, allowing disengagement of the workpiece from coupling portion 211. Drive member 21 is received in compartment 121 with a top edge abutting an inner face of annular end wall 122 and with toothed portion 213 aligned with first groove 124. At least one pawl 22 is received in the first groove 124 and supported by partitioning wall 123. Pawl 22 includes a toothed portion 221 and an arcuate actuation portion 222. A switch 15 is rotatably received in second groove 125 and includes a stem 151 extending beyond first side F1 for manual operation. Switch 15 further includes an actuation end 152 abutting against actuation portion 222. When stem 151 is manually rotated between two positions, actuation portion 222 is actuated such that toothed portion 221 is selectively in one of first and second engagement relations with toothed portion 213 to allow drive member 21 to drive an object coupled with coupling portion 211 in one of two opposite directions. A C-clip 24 is mounted in annular grooves 214 and 126 and includes two hook-shaped clamping portions 241 received in recess 13. Drive member 21 is rotatably retained in compartment 121 by C-clip 24. A user can use a pair of pliers to release C-clip 24 from annular grooves 214 and 126 and recess 13 by clamping one of clamping portions 241, allowing removal of drive member 21 from compartment 121 for maintenance.
However, dust and debris D will accumulate in exposed recess 13 and enter compartment 121 along a path indicated by arrows shown in FIG. 2. Dust and debris D entering a gap between toothed portions 213 and 221 will cause abrasion and damage to toothed portions 213 and 221, leading to malfunction of ratchet wrench 10′. Dustproof device in recess 13 is, thus, required.
U.S. Pat. No. 5,533,427 discloses a ratchet wrench having a retaining plate engaged with a bottom surface of a pawl. A clamping ring is mounted below the retaining plate and has an ear. The retaining plate supports the pawl, which is similar to portioning wall of ratchet wrench 10′ in FIGS. 1A and 1B. However, the retaining plate must be made of metal. Furthermore, dust and debris can accumulate in a location outside of the clamping ring and then enter a gap between a ratchet wheel and the pawl via the ear, failing to provide satisfactory dustproof effect.
Thus, a need exists for a reliable, inexpensive ratchet wrench with reliable dustproof effect.